Introduction
Magnesium (Mg) is a ubiquitous element in nature. Both plants and animals have an absolute requirement for magnesium, a mineral that plays a central role in photosynthesis in plants, and many of the metabolic reactions in animals.

Magnesium is a cofactor in over 300 enzymatic reactions in human beings. It is required for sodium, potassium, and calcium homeostasis, as well as for the formation, transfer, storage, and utilization of ATP (the energy currency in our body) at the cellular level. You cannot live without magnesium. The lower the cellular level of magnesium, the faster disease states develop and the faster aging progresses. It's that simple.

The fact is that only about 25% of Americans meet the Recommended Dietary Allowance (RDA) of 300 - 400 mg per day for magnesium. Most American women get only 175 - 225 mg per day, and men 220 - 260 mg. To get enough magnesium from the diet, one needs to consume about 2000 calories a day. Nuts, whole grains and legumes are high in magnesium.

A. Low Dietary Magnesium Levels from the North American Diet: In countries where a refined diet is the norm, such as North America, there is a universal deficiency in magnesium intake from the diet. 99% of the magnesium in sugar cane is lost when it is refined to white sugar. 80 - 96% of magnesium content in wheat is removed when refined to white flour. Magnesium is not added back to the soil, nor to "enriched flour" after the germ and bran layer have been removed. 50% of the magnesium may be lost during the cooking process into cooking water. The Asian diet, which is whole-food based, typically provides 500 - 700 mg of magnesium per day, while the Western diet provides one-third that amount.

B.Intestinal Absorption:Consumption of soft drinks (pop or soda) decreases the body's absorption of magnesium. In the intestines, the phosphoric acid in soft drinks and the phosphates in baking powers combine with the magnesium to form magnesium phosphate, an insoluble precipitate that is excreted through the feces.

The typical high-dairy, high fatNorth American diet contains almost four times as much calcium as magnesium. This unbalanced ration coupled with the high fat content tends to suppress magnesium absorption. Further, high levels of dietary or supplementary magnesium tend to suppress calcium absorption.

Excessive supplemental calcium taken to encourage bone growth in children and prevent osteoporosis in adults leads to a decrease in magnesium absorption.

To maximize dietary absorption of magnesium, give up ice cream (which is often high in sugar and fat), chocolate (high in sugar and fat), soft drinks (high phosphate content), loud music (noise = stress), pizza (high in fat), milk shakes (high in calcium, sugar and fat), and potato chips (high in salt and fat). Does this sound like something the average American could do?

C. Urinary and Fecal Magnesium Loss: Magnesium can be recycled through the kidneys, with a 95% recovery rate. However, alcohol promotes magnesium loss, as do diets high in animal protein, sugar, sodium, and calcium. High blood levels of adrenaline and cortisol (hormones released during stress) cause serious urinary magnesium losses. Excessive noise and heat stress also promotes urinary magnesium losses. Blood Test for Magnesium Level

60% of the magnesium in our bodies exists in our bones, 39% in our cells, and only 1% in the blood. The correlation between blood magnesium and intracellular levels is poor. Total body magnesium levels may decrease 20% during a fast, with no change in blood levels. While low blood magnesium levels may correctly indicate serious disease, a "normal" magnesium blood level by traditional laboratory test may exist concurrently with a deficit in intracellular magnesium. No reliable test of tissue magnesium level is currently available. An inconvenient, but accurate method to measure magnesium levels is by a 24-hour urine measurement for magnesium after intravenous magnesium loading. This is seldom done due to patient compliance issues.

The National Research Council recommended minimum daily consumption for magnesium is 150 - 250 mg for children under 10 years of age, and 300 - 400 mg for adults. Current statistics show that only 25% of surveyed populations have a magnesium intake at or greater than the RDA. Almost 40% consume less than 70% of the RDA. It is fair to say that the majority of the North American population has a sub-optimal intake of magnesium.

RDA for magnesium is about 2 mg per pound body weight. The American diet typically provides 1.2 - 1.5 mg per pound of body weight. Many magnesium experts believe that an intake range of 2.7 - 4.5 mg per pound (about 400 - 700 mg a day) is optimal. Some on the forefront of magnesium research are recommending up to 1000 mg per day for healthy people, using the clinical symptom of diarrhea as a target marker. Once the marker is achieved, magnesium intake can be reduced. Asians, for example, are already taking 3 - 4.5 mg of magnesium per pound of body weight.

The use of calcium supplementation for the management of Primary Postmenopausal Osteoporosis (PPMO) has increased significantly since 1987, the year when the National Institute of Health increased their recommended daily intake of calcium to 1,500 mg for prevention of PPMO. This recommendation was made in spite of the different conclusions made by some clinical studies presented in the same proceedings. Results of some of these controlled studies presented showed no significant effect of calcium intake on mineral density on trabecular bone and only a slight effect on cortical bone. Since PPMO is predominately due to demineralization of trabecular bone, there is no justification for calcium mega-dosing in post-menopausal women. In fact, soft tissue calcification can be a serious risk factor during calcium mega-dosing under certain conditions. Certain investigators, notably Dr. Guy Abraham, postulated that atotal dietary program emphasizing magnesium instead of calcium for the management of PPMO would be more effective for preventing bone loss. His concerns about low magnesium for osteoporosis are similar to his concerns for women with premenstrual tension syndrome.

To test Dr. Abraham's hypothesis, 19 postmenopausal women on hormonal replacement were given a supplement consisting of 500 mg calcium (50% of RDA) and 600 mg of magnesium (200% of RDA). Serial bone density studies were conducted every 3 months. Subjects receiving the treatment showed an 11% increase in mean bone density versus 0.7% in the untreated group. Results also showed that in postmenopausal women on hormonal replacement therapy, the magnesium emphasized program resulted in a calcaneous bone density 16 times greater than that of dietary advice alone. At the start of the study, 15 subjects were below the fracture threshold. After a year of treatment with magnesium supplementation, only 7 of them were below the fracture threshold.

Researchers such as Dr. Abraham further postulate that PPMO is predominately a skeletal manifestation of chronic magnesium deficiency, facilitated by estrogen withdrawal during the postmenopausal period. He suggested raising the RDA of magnesium to 1000 mg/day and lowering the RDA for calcium to 500 mg/day. His proposed daily intake for calcium would be more in line with the World health Organization's "practical allowance" of 400 - 500 mg daily for adults. Such a reversal of the magnesium/calcium ratio would most probably lower the incidence and prevalence of many other degenerative diseases as well.

B. Prevention of Cardiovascular Diseases (CVD)Cardiovascular diseases have been often been linked to magnesium depletion. One of the most alarming trends in the past half-century is the sharp increase in sudden deaths from ischemic heart diseases, particularly in middle-aged men who suddenly develop myocardial infarction, cardiac arrhythmias, or cardiac arrest. It has been postulated that magnesium deficiency may be a common etiologic factor.

Magnesium is found in high amounts in nuts like almonds and peanuts. Research has found than nut lovers (those who eat nuts 5 times a week) have half the chance of developing a heart attack compared to those who eat nuts only once a week.

Epidemiological studies provide compelling evidence. The lower death rates from coronary heart diseases (CHD) in Japan, China, India, and Italy versus those in Europe and America point to differences in cholesterol and saturated fat consumption as being the primary causative factor.

Not to be forgotten, and perhaps even more critical, is the role of dietary salt in contributing to these differences in death rate. In countries with lower CHD death rates, most of the magnesium comes from table salt that is derived from seawater through an evaporative process. This type of table salt contains calcium, potassium, and large amounts of magnesium, in addition to the sodium.Table salt used by North Americans comes primarily from salt mines. As a result of being washed with hydrochloric acid and recrystallization, this purified salt contains almost pure sodium chloride. The Japanese consume 10 grams of ocean salt a day. This provides approximately 1500 mg of magnesium. This is almost four times the magnesium recommended in the RDA and five times more than the average American gets.People from the countries using sea salt suffer a higher incidence of hypertension and stroke (probably due to the higher sodium intake) but lower rate of CHD (probably due to their higher magnesium intake). With increasing use of pure sodium chloride in these countries over the past 20 years, it is interesting to note that the incidence of CHD has increased accordingly.

A variety of cardiac arrhythmias have been associated with magnesium dis-equilibrium, including ventricular tachycardias, fibrillations, and ectopic beats. Coronary spasm is also a major pathogenic feature of hypo-magnesemia. For patients with variant angina, 24-hour magnesium retention after intravenous magnesium loading was 60%, while it was only 36% in control subjects. Substantial evidence has associated magnesium deficiency with sudden cardiac death, a condition that claims 300,000 lives every year.

Deficiency in magnesium, aside from having a negative impact on the energy production pathway required by mitochondria to generate ATP, also reduces the threshold antioxidant capacity of the cardiovascular system and its resistance to free-radical damage. Vitamin E has been found to have strong protective properties against magnesium deficiency-induced myocardial lesions and cardiomyopathy. Magnesium acts as an antioxidant against free radical damage of the mitochondria. It has been called nature's "calcium channel blocker" because of its ability to prevent coronary artery spasm, arrhythmias, and to reduce blood pressure.

C. Pre-menstrual Syndrome, Diabetes, Depression, and Chronic Fatigue
Women affected by premenstrual syndrome have been found to have reduced magnesium levels. Since magnesium is a cofactor in hundreds of enzymatic reactions, many of which govern cell membrane function, it is easy to see how magnesium can play a fundamental role in multiple organ systems, although there is no conclusive proof that links low magnesium levels directly to PMS.Magnesium plays the role of a second messenger for insulin action. Insulin itself has been shown to be an important regulatory factor for intracellular magnesium accumulation. Dietary magnesium supplements have been shown to improve both insulin response and insulin action in non-insulin dependent diabetics.Magnesium also helps regulate nerve cell function. Its presence in adequate amounts in the synaptic gap between nerve cells controls the rate of neuron firing. Nerves fire easily when magnesium levels are too low. The effect of this rapid firing is increased sensitivity to stimulation of all kinds. Noise will sound excessively loud, emotional reactions will be exaggerated, and the brain may be too stimulated to sleep. Magnesium deficiency may cause excessive muscle tension (such as spasms, tics, and restlessness) because magnesium is needed at the neuro-muscular junction to allow muscles to relax. Chronic fatigue is another common clinical entity associated with deficiency of magnesium.A deficiency of magnesium can present common psychiatric symptoms including depression, anxiety, restlessness, and irritability. Depressed patients have been found to have lower levels of magnesium. Oral supplementation of magnesium has been tried as an adjunct treatment in psychiatric patients and been found to be successful in rapidly cycling bipolar affective-disorders. Discussion

Magnesium is perhaps the most under-appreciated mineral in our lives. Over 75% of Americans are deficient, even by the low standards set by the RDA. Physicians and anti-aging researchers alike are now recognizing the growing clinical importance of magnesium.

Magnesium supplementation is recommended for healthy patients as well as for those with osteoporosis, cardiovascular disease, depression, diabetes, chronic fatigue syndrome, premenstrual syndrome, and hypertension.

Magnesium deficiency, at the intra-cellular level, is difficult to measure. Blood tests using traditional laboratory methods do not give a good indication of magnesium level from an optimum health and disease prevention perspective. One's blood test can be "normal" while the intracellular level is "deficient."

The decision to give magnesium supplementation should therefore rely on evaluation on predisposing factors and symptoms. 100 - 200 mg supplemental magnesium with each meal(three times a day)seems a reasonable and safe recommendation for people with normal kidney function and for those not regularly taking magnesium containing laxatives or antacids. This level of supplementation, coupled with the average dietary magnesium intake, would bring the total daily consumption in line with the 400 - 700 mg a day advocated by many researchers and nutritionally oriented clinicians for optimum health.